Method and apparatus for determining a need for a change in a pixel density requirement due to changing light conditions

Abstract

There is provided a method for determining a need for a change in a pixel density requirement due to changing light conditions. The pixel density requirement specifies a pixel density which enables identification of an object in images captured by a camera. The method comprises receiving and monitoring (S02) a camera setting which is indicative of a light condition to which the camera is subjected and which affects the quality of images captured by the camera, and determining (S06) that there is a need for a change in the pixel density requirement upon detection (S04) of a change in the camera setting. The camera setting includes at least one of a gain and an exposure time used by the camera when capturing images.

Description

TECHNICAL FIELD[0001]The present invention relates to the field of camera surveillance, and, in more detail, to identification of objects in accordance with a pixel density requirement in images captured by a camera. In particular, it relates a method, an apparatus, and a system for determining a need for a change in a pixel density requirement due to changing light conditions.BACKGROUND[0002]Camera surveillance has become more and more common. Images captured by surveillance cameras are for example used as evidence in police investigations and legal trials for the purpose of identification of objects, such as the face of a suspect or the numbers on a license plate.[0003]In order for the object identification to be valid as legal evidence, the resolution of the object in the image must be high enough, i.e. the object must cover a certain amount of pixels in the image. This is usually expressed in terms of a pixel density requirement specifying a pixel density (e.g. measured in pixel...

AI Technical Summary

Benefits of technology

[0026]Another example of an event is to overlay an indication on the images captured by the camera showing in which part of the field of view the identification may be correctly done under the current light conditions. Yet another example of an event is to automatically direct another movable camera towards the interesting monitoring area to increase the monitoring efforts.

Problems solved by technology

However, the pixel density requirements as for example recommended by police authorities are only valid under optimal light conditions.

When scene conditions change, for example when the light level changes, the recommended pixel density requirement may not be enough to ensure a legally valid object identification—a higher pixel density may well be required.

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